Attachment for transits and other surveying-instruments



(No Model.) zsneets-sheet l.

. R. GIBBONS.

ATTACHMENT FOR TEANSITS AND OTHER SURVEYING INSTRUMENTS. No. 275,034. Patented Apr.3.1883.

FIG. I-

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(No Model.) 2 Sheets-Sheet 2.

R, GIBBONS.

ATTACHMENT FOE TRANSITS AND OTHER SURVEYING INSTRUMENTS. N 275.034.- Patented Apr. 3, 1883,

FIG. 3 I) UNITED STATES PATENT I OF ICE.

ROBINSON GIBBONS, OF ALAMEDA, CALIFORNIA.

ATTACHMENT FOR TRANSITS AND OTHER SURVEYING INSTRUMENTS.

SPECIFICATION forming part of Letters Patent No. 275,034, dated April 3, 1883.

Application filed November 13, 1882. (No model.)

To all whom it may concern:

Be it known that I, ROBINSON GIBBoNs, of Alameda, county of Alameda, State of California, have invented an Improved Attachment for Transit and other Surveying-Instruments; and I hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to an attachment for transit'and other surveying-instruments; and it consists in novel features of construction and combination of parts, all as will be hereinafter fully described, and setforth in the claim hereto annexed.

The object of this invention is to render it possible to direct the telescope to a point heneath the instrument. 7

Referring to the accompanying drawings for a more complete explanation of my invention, Figure l is a side elevation, showing the supplemental plate and its are lying flat, and the telescopeinitsordinaryposition. Fig.2shows the plate raised and clamped to the arc, the telescope directed downward. Fig.3 is an end view of the same.

B is the plate which usually supports the telescope of a transit or other similar surveyinginstrument having the needle-box E, graduated divisions, verniers, and other attachments usual to such instruments,and ameansfor mounting it upon a tripod or other support.

A is a supplemental plate, formed preferably in an arc of a circle, so as to coincide with the plate B, upon which it is supported. This plate A is hinged to one side of the plate B at F, and when let down upon it is parallel or level with it.

G are the standards, upon which the telescope H is mounted, and these standards are secured to the plate A, so as to partake of its motion.

D is a vertical arc, and O is a clamp upon the rear side of the plate A, which travels upon this are when the plate is turned up or down he clamped in any desired position.

about its hinges, and by which the plate may This are D is jointed near the bottom, so that when the plate A is horizontal upon the plate B the are may be folded down out of the way for the ordinary operations of the instrument.

Whenever it is desired to use the telescope at an angle more nearly vertical than can be attained upon the plate B, as ordinarily constructed. the plateAis lifted about its hinges, and the clamp-screw O is fixed so as to hold the plate A rigidly to the are D, when the telescope may be made to assume a position similar to that shown in Fig. 2.

This device is especially useful in laying out the direction of an underground-driftin a mine upon the surface. In such a case the instrument may be set above a shaft and the telescope turned down, so that two points may be determined upon a line, which leads across the shaft and into the drift. This avoids the danger of mistakes on account of an aberration of the compass, which often occurs below the ground, and the direction being once fixed the remainder may he made to correspond upon the surface and below.

When not in use these supplemental parts may be folded down out of the way,.as before described.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- The supplemental plate A, hinged to the plate B, and having the standards G of the telescope E fixed to it, in combination with the clamp 0, and the are D so hinged as to stand vertically for use, or to lie horizontally when not in use, substantially as herein described.-

In witness whereof I hereunto set my hand.

ROBINSON GIBBONS.

Witnesses:

S. H. NoURsE, G. W. EMERSON. 

